Safety valve



Sept. 15; 1331. w. HARGREAVES SAFETY VALVE Filed NOV. 5. 1929 .:s R s owmw n m w NYC 4 0 E K MIT a A 2& W

Patented Sept. 15, 1931 f.

m s e T T O I we WILLIAM HARGREAVES; or WEST ,DIDSBURY, MANCHESTER, ENGLAND, ASSIGNOB' or ONE-HALF To an ROSS AND COMPANY LIMITED, or s'rocxronr, ENGLAND sun'rr VALVE Application filed November iseafseria 110404 927, and in great Britain November 22, i928.

'This invention relates to safety valves for steam generators, or vessels under fluidpressure, and particularly to-safety valves for locomotive boilers. v

The objects in view are, first,"to facilitate or simplify testing and exact setting of such valves in the actual manufacturing shop so that the valvescan be issued to conform with a more or less dead test, second, topermit '10 of and limit adjustment of unlt valves up or down within strictlynarrow limits by little skilled persons or of narrow relative ad-. justment in grouped and interconnected safety valves, and, thirdly, to permit :of

. greater adjustment in such unit safety valves up or down (but still within limits) by an inspector or skilled. ofliciaL; All 'the'se objects can be readily accomplished with prop.- er safeguards according to mywinvention,

facility as regards testing and setting on test, the second object is'desirable to give some margin up or downin the unit or for groups of safety valve units interconnected after the fashion disclosedinpatent specification 1,665,850, Whilst the third'object is a convenience which can with advantage be rendered available to an inspector'who may havefto deal with safety valves which have been repaired or reassembledorsubsequently'tested with less skill and less perfect means than those at the disposal of the actual manufac- 'turer. 7 e i The accompanying drawings show certain simple means by which the objects set forth and according to my invention can be achieved.

In these drawings Fig. 1 is asect1onalelevation of the up-.

40 per half of one type of safety valvewith oer tain suitable additional means appropriately combined. 1 v I Fig. 2 shows a planview of Fig. 1. Fig. 3 is a diagram indicating the coupling .45 or cross-connection of'tWo safety ,yalvesfin for my purpose and these in connection with The first object isdesirable as it ensures I lower ez rterlor screw thread which is screwed exterior to the main casing at all times, so that this exterior part is readily accessiblefor adjustment up or down. There is an annular flange a or other abutment on the screw adjacent to a movable settable ring Z) which Parallel, h S y ve'havin combined with it mechanism described. v e

To further ascertain the natureof myinvention, I shall now describe simple means akin to what is hereafter the well. known fRoss. type of safety valve, without many way restricting myinvention to safety' valves of such type.

All valves of the Ross type have an ex- 7 terior caslng such as 1, a valve seatand valve (not shown) valve spindle '2,spring 3 etc,

and it is very'vcommon to'employ a secondary area or top cap such as 4 and a settable top plate 5. Then there is nut structure or sealed cotter' 6 combined with the spindle. There is always some form of adjustable deviceor compression screw which regulates the compression on the contained spring.

Ilprefer to use an adjustable device a with upordown in the upper end of the valve cas- 1ng Ito requirements at the test, and this is so constructed that part of its structure. is

threaded adjustable device a which works for convenience can'be applied on the screw threaded upper end of the exterior of the main easing 1. This settable ringb can (after testing ofthe safety valve) beset, to

resist the screw threaded adjustable device a. being further screwed Y down beyond what 'wouldfor example put a further load. of say 4:1bs'. per square inch on the valve. Thissete table ring I) can be fixed (after adjustment) safeguarding device.

by a pin 6, spot welded in place,'or by'other,

As a result, no person can turn downj the V screw-threaded device a from an, approved setting to a greater extent than theijlbs.

I only. intend ,asemi-skilled person fto be} 7 ableto turn down to the extent of say 2 lbs.

The protruding upper part of the screwthreaded adjustable device a is fashioned to adjustable device a.

receive an annular cap 0 which is like a split ring, being sawn through at c. This annular cap 0 can be clamped or fixed by a bolt 0 or any equivalent device capable of receiving a seal. Said annular cap or split ring 0 has a fixed or adjustable vertical pin 0 the lower or inner extremity ofwhich de ends into a concealed segmental slot a cut 1n the annular upper edge of the screw-threaded Said annular cap or split ring .0 hasalso, a'hori'zontal or other lever extension 0.. for manual operation (or for coupling to a similar lever extension of another kindred safety valve when unit safety valves are cross-connected according to Patent- Nofl,665,850') and from this lever extensionl arrange a bolt or stud which fits a curved slot 0 1n an extension from the settable' ring 6. The'slot could be in the lever extension. This bolt or stud (Z has its lower end sealedto prevent Withdrawal or tampering. The slot 0 is ofsuch dimensions that itonly permits the bolt or stud d to move to such an amount as allows the screw threaded adjustable device a to be moved-over a range of say 4: lbs, i. e. say 2 lbs. up and 2 lbs.

down. As a'consequence, whn'the complete safety valve is tested, sealed-up and mounted, the semi-skilled person can only effect an adjustment ofsay 4l1 lbs.'in total as a maximum, or cross-connected valves working-in parallel canonlyl-be relatively"adjusted to that extent.

j] But,'for'tl1e highly skilled person, a may be authorized to break the sealof the bolt 0 for the annular cap or split ring 0 and slacken such bolt back.- This frees the screwthre'aded adjustable .device'a and allows same to be turned by any tool or provided means ,to the extent of the concealed segmental slot e Such concealed segmental slot a may be vsuch size as will permit the screw-threaded adjustable device'a to be turned to an extent of say 8 lbs., that is, 4 lbs. up'and 4 lbs. down. Thus, the range ofadjustment available to the skilled person can be much greater than to the semi-skilled. The number of lbsfo-f adjustment permissible up or downis obviously variable in either case.

The construction or meanscan be much varied, so long as I combine with the, head of the safety valve casing externally operated mechanism which permits a semi-skilled ,adjustment or of cross-connectionlof safety valves working in parallel, along with greater latitude of adjustment available (on the breaking of a seal) to the skilled official.

=WVhilstonly an inspector may use the perf'missible major? adjustment of the adjustablede'vice to themaximu-m, the minofl r justment or changeby the semi-skilled person "is always availablebothfup and down. Asa

limit'stud set back in the slot.

' controlled and minor adjustment for slight variation; of. settingand operable by the semi-skilled, or for group safety valve coupling purposes. 1

In the general arrangement suggested, it is possible to get the major adjustment Withouthaving to use any-tool with the screwthrea'ded adjustable device, because, when the inspector breaks theseal or bolt 'c and releases the annular cap or split ring a, the same'is free on its bearingon-the screwthreaded adjustable device a and can be manipulated. Being f'1'ee,"'the lever extension can be moved angularly a limited distance in either direction as may be required and the This done, the annular cap orsplitjring can be temporarily fastened up again, and so the lever extension can makesay double the'movement on actuation, thus enabling the inspector to operate the screw-threaded adjustable device a an augmenteddistance Without the use" of any special tools. Before the inspector finally locks-up the annularcap' or split ring 0, he sees'the setting issuch' as will only'permit the semi-skilled to effect the minor adjustment or movement. r

' The dia ram Fig. Sis intended to indicate two ustable' safety valves of the character above set forth and cross-connected or coupled on the system according to my United States Patent N o. 1,665,850, it beingv apparent that the twosafet'yfvalves A and B can be made with screw threads of the same hand and have their leverarm extremities 0*, c coupled by the connecting rod 0 whereby, as the connecting rod 0 is actuated in one direction or'th'e other, there'lative setting of thetwo'safety valves'isletfected from time to time all as is'set fOl'thiII the said Patent No. 1,665,850. j it H v ldeelare that wliat I'clai1n-is:

l A'n 'adjustment mechanism for safety valves, comprising in combination, a valve casing, a valve-tensioinspring in said casing, means for effecting a'minorchange in the tension of the spring, means for limiting said tension-changing means: within predeter mined limits, normally inoperative means associated with said tension-changing means 1 and disposed within the casingfor'etfecting a further change oftension within'predeter- "Inin'e'dlimits, and means permitting access to said normally inoperative means to enable said further change of tension to be effected but still within predetermined limits.

2. An adjustment mechanism for safety valves, comprising in combination, a valve casing, a valve-tension-springin said casing, a member threaded in said casing and adapted to maintain said spring at a predetermined tension, a member adjustable on the outside of the casing, means for securing said adjustable member in fixed position, means carried by the tension-maintaining member and adapted to contact with said outside member for tension-maintainin g member in one direction, means releasably secured to the tension-maintaining member for actuating the same, and

cooperating means carried by said tensionmaintaining member and said outside mem-' her for limiting the movement of said actuating means.

3. A11 adjustment mechanism for safety valves, comprising a casing, a settable device thereon, means for securing said settable device in fixed position on the casing, a sleeve threaded into the casing and having an abutment adapted to engage said settable device thereby to limit movement of the sleeve in one direction, a split ring releasably secured-to the sleeve for rotating the latter,

- for rotating'the cap,

limiting the movement of the said ring 1 having a lateral extension for actuating the V WILLIAM HARGREAVES.

ring, cooperating means carried by. said exa tension and said settable device for limiting the actuation of the ring, said sleeve-being independently movable when the split ring is released, and cooperating means carried by the ring and sleeve for limiting said independent movement.

4. An adjustment mechanism for safety valves, comprising a casing, a settabledevice thereon, means for securing said settable device in fixed position on the casing, a sleeve threaded into the casing and having an abutment adapted to engage said settable device thereby to limit movement of the sleeve in one direction, a rotatable cap mounted on the sleeve, releasable means for securing the cap and sleeve for rotation together,means for actuating said cap, cooperating means carried by said cap ing the action of said actuating means within predetermined limits, the sleeve being rotatable independentlyjwhen the cap-securing means is released, and cooperating means carried by the cap and sleeve for limiting said independent rotation.

5. An adjustment mechanism for safety valves, comprising a casing, a settabledevice I thereon, means forsecuring said settable device in fixed position on the casing, a sleeve threaded into the casing and having an abut ment adapted to engage said settable device thereby to limit movement of'the sleeve" in one direction, a rotatablecap mounted on the sleeve, releasable means for securing the cap and settable device for limit- 

